Process for production of molecular devices

ABSTRACT

An object of the present invention is to provide a method of effectively producing a nano-particle and a nano-wire, and others.  
     Specifically, the present invention provides a method of producing a molecular device including: the use of a molecular structure having a higher atomic density in the periphery than in the interior and bonding residues in the periphery; and a step of crosslinking the bonding residues, and the method of producing a molecular device according to claim  1 , characterized in that the molecular structure is constituted by a skeleton portion having a skeleton structure, and a terminal portion which is arranged in the outer shell of the skeleton portion, has a higher atomic density than that of the skeleton portion and has bonding residues; and that in the step of crosslinking the bonding residues, the bonding residues in the terminal portion of the molecular structure are crosslinked to form the molecular structure into a shell structure, and others.

This application is a divisional of Ser. No. 10/509,380, filed Sep. 27,2004, which is a National Stage Application Under 35 U.S.C. § 371 ofPCT/JP03/03669, filed on Mar. 26, 2003 which is based upon and claimsthe benefit of priority from prior Japanese Patent Application No.2002-91548, filed on Mar. 28, 2002 and Japanese Patent Application No.2002-94211, filed Mar. 29, 2002, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method of producing a molecularaggregate of which the linked form is controlled in a molecular level,by irradiating a molecular structure having a bonding residue in theperiphery with light, and through taking advantage of the photochemicalprocess and the photophysical process, selectively and effectivelycombining the periphery of the molecule or mutual molecular structures.By applying the present technique, it becomes easy to make variousthree-dimensional molecular devices of highly dense molecules.

BACKGROUND ART

The present silicon semiconductor element has remarkably improved theability of computers by its hyperfine structure and integrated structureinto high density. In the silicon semiconductor elements, an n-type orp-type semiconductor is made by doping a very small amount of impuritiesinto silicon. However, by a progress of hyperfine processing, the numberof impurity atoms contained in one element has been extremely decreased,and as a result, the element cannot work as a be the limit is aplurality of tens of nm, and if a hyperfine processing technologyadvances at a current pace, it is predicted that the limit will bereached after a plurality of tens of years.

In a fine processing technology by optical lithography using a chemicalamplification type photo resist, the applied light has been shifted fromvisible light to ultraviolet light or deep ultraviolet light, but thelimit of resolution is considered to be about 70 nm. Recently, anapplication of lithography using an X-ray, a focused ion beam and anelectron beam, which have shorter radiation wavelengths has beeninvestigated. However, in order to use these radiation wavelengths, thedevelopment of a new photo resist, an electron beam resist, an opticalsystem and a mask, and the reduction of a manufacturing cost arenecessary and expected. However, the technical and practical problemshave not been improved yet at this stage. Accordingly, the technologybased on a top-down concept reaches a limit.

As for a technology based on a bottom-up concept, a technique using ascanning probe microscope captures attention at present. One of thetechnologies can make a nanometric structure by disposing and reactingatoms or molecules in an arbitrary place with the use of a scanningtunneling microscope (STM). The study is described, for instance, in ascientific magazine, Nature, 409, 683 (2001) by Y. Okawa and M. Aono.Another technology has succeeded in the production of aself-organization film which is patterned in a nanometric order, bydrawing the pattern on a substrate with a solution of thiol moleculescoated on the top of a fine needle in an atomic force microscope (AFM).The study is described, for instance, in a scientific magazine, Science,283, 661 (1999) by R. D. Piner, J. Zhu, F. Xu, S. Hong and C. A. Mirkin.Both technologies are excellent techniques for making a two-dimensionalstructure in a nanometric region, but are difficult to construct athree-dimensional structure, and are not practical from the viewpoint ofa manufacturing cost.

The above-described methods for making a device are based on the conceptof the so-called top-down technology, and have difficulty in producing athree-dimensional molecular device having a smaller size.

At present, a new molecular device of highly dense molecules, which canbe operated even though having a dimension of a nanometric level, isenergetically developed in a worldwide scale. For instance, a singleelectron element capable of controlling the switching on and off withone electron, and a molecular device using a functional organic moleculeas a molecular structure are proposed. In order to put the moleculardevices based on new concepts to practical use, many problems must bestill solved. One big problem among them is how to selectively combineindividual molecules. This is the big problem of the bottom-uptechnique, and is mentioned in Nikkei Science of a scientific magazine,2001, December, page 37. However, an effective method for controllingthe coupling of individual molecular elements has not been found untilnow.

DISCLOSURE OF THE INVENTION

As a result of intensive research for the purpose of solving the abovedescribed problems, the present inventors have found that each molecularstructure necessary in making a molecular device of highly densemolecules, can be combined by photoirradiation or the like. At least oneproblem out of the above described problems is solved by the inventiondescribed below.

(1) The first invention according to the present application is “amethod of producing a molecular device including: the use of a molecularstructure having a higher atomic density in the periphery than in theinterior and bonding residues in the periphery; and a step ofcrosslinking the bonding residues”. For instance, a dendrimer has ahigher atomic density in the periphery (the branch part) than in theinterior (so-called the core part). In the present invention, amolecular device is produced by thus using a molecular structure havingbonding residues in the periphery (the outside region) among molecularstructures having more atoms in the outside region of a molecule than inthe vicinity of the center of the molecule, and crosslinking (includingcombining) the above described bonding residues. By crosslinking thebonding residues in a molecular structure, nano-particles and nano-wirescan be produced, and by using these, a molecular device havingfunctional molecular structures and functional molecular aggregatesassembled at a high density, can be produced.

(2) Another invention according to the present application is “themethod of producing a molecular device according to the item (1),characterized in that the molecular structure is constituted by askeleton portion having a skeleton structure, and a terminal portionwhich is arranged in the outer shell of the skeleton portion, has ahigher atomic density than that of the skeleton portion and has bondingresidues; and that in the step of crosslinking the bonding residues, thebonding residues in the terminal portion of the molecular structure arecrosslinked to form a shell structure in the molecular structure”. Themolecular structure thus acquiring the shell structure is also called anano-particle. The nano-particle has a space in a shell, and can includevarious materials.

(3) Another invention according to the present application is “themethod of producing a molecular device according to the item (1) or (2),wherein the bonding residue is an optically bonding residue”. Becausethe bonding residue is the optically bonding residue, the reaction canbe controlled by photoirradiation.

(4) Another invention according to the present application is “themethod of producing a molecular device according to any one of the item(1), (2) or (3), wherein the bonding residue has at least one of one orboth of a double bond and a triple bond”.

(5) Another invention according to the present application is “themethod of producing a molecular device according to the item (1) or (2),wherein the bonding residue is any one of a cinnamic acid group, anα-cyano cinnamic acid group, a coumalin group, a chalcone group, acinnamylidene acetate group, a p-phenylene diacrylate group, anacetylene group, a diacetylene group, a diphenyl acetylene group and ananthracene group”. These groups are effectively coupled, and areeffective for crosslinking such as intramolecular coupling andintermolecular coupling.

(6) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(1) to (5), wherein the molecular structure is a dendrimer”.

(7) Another invention according to the present application is “themethod of producing a molecular device according to the item (6),wherein the dendrimer is expressed by the following formula (I) or(II)”:

wherein n represents an integer of 10 or less, and

wherein n represents an integer of 10 or less and R represents a linkagegroup.

Here, in the general formulas (I) and (II), n is an integer of 1 to 10,preferably of 2 to 10, and further preferably of 3 to 8. In addition, R(a coupling group) in the general formula (2) includes, for instance, analkenyl group with C₁ to C₁₀ and an alkynyl group with C₂ to C₁₀, but isnot particularly limited so far as being a coupling group used for thedendrimer.

(8) Another invention according to the present application is “themethod of producing a molecular device according to the item (7),wherein R in the general formula (II) is an alkenyl group with C₁ to C₁₀or an alkynyl group with C₂ to C₁₀”.

(9) Another invention according to the present application is “themethod of producing a molecular device according to the item (7) or (8),wherein each n in the general formulas (I) and (II) is an integer of 2to 10”.

(10) Another invention according to the present application is “amolecular structure (a nano-particle) having a shell structure made bycrosslinking the bonding residues of the molecular structure which has ahigher atomic density in the periphery than in the interior and has thebonding residues in the periphery, into a shell”.

(11) Another invention according to the present application is “amolecular device including the molecular structure having the shellstructure according to the item (10)”.

(12) Another invention according to the present application is “a methodof producing a molecular device including: the use of a molecularstructure having a plurality of bonding residues in the molecule, and asensitizer; and the step of joining the bonding residues of themolecular structure by an energy imparting step of imparting energy tothe sensitizer, to obtain the molecular structure having a shellstructure”. The energy imparted to the sensitizer propagates to themolecular structure. The energy having propagated to the molecularstructure is used for joining the bonding residues. Here, “plurality”for the number of bonding residues means 2 or greater, and thoughvarying with the structure of the molecular structure, the number ofbonding residues is normally 4 or greater but 1,000 or less, preferably8 or greater but 512 or less, and further preferably 16 or greater but255 or less (hereafter, the same). The molecular structure obtained insuch a step includes a functional nano-particle having a shellstructure, and a molecular device comprising the functionalnano-particles has various functions according to the properties of thevarious nano-particles.

(13) Another invention according to the present application is “a methodof producing a molecular device including: the use of a molecularstructure having a plurality of bonding residues in the molecule, and asensitizer; an energy imparting step of imparting energy to thesensitizer; one or both stages of an energy transfer process oftransferring the energy to the bonding residues from the energy-impartedsensitizer, and an electron-imparting process of transferring electronsto the bonding residues from the energy-imparted sensitizer; and a stepof obtaining the molecular structure having a shell structure by usingthe energy transfer process or the electron-imparting process as adriving force for the chemical bonding reaction of the bondingresidues”. The molecular structure obtained in such steps includes afunctional nano-particle having the shell structure, and a moleculardevice comprising the functional nano-particles has various functionsaccording to the properties of the various nano-particles.

(14) Another invention according to the present application is “a methodof producing a molecular device including: the use of a molecularstructure having a plurality of bonding residues in the molecule, asensitizer and a crosslinking agent containing a plurality of bondingresidues; and the step of crosslinking the bonding residues in themolecule of the molecular structure with the crosslinking agent by usingan energy imparting step of imparting energy to the sensitizer, toobtain a molecular aggregate which three-dimensionally combines aplurality of molecular structures”. The molecular assembly obtainedthrough such a step includes a nano-wire. One example of the nano-wireincludes one having the molecular structures regularly disposed. Eachmolecular structure functions as a molecular device having variousfunctions such as an optical memory effect. In addition, a molecularaggregate (or a molecular device) having various functions can beproduced by combining the molecular structures one-dimensionally,two-dimensionally and three-dimensionally one after another into alinear shape, a grid shape or a radical shape. The position where themolecular structure is combined, can be controlled by controlling theposition of the bonding residue in the molecular structure, which leadsto a control of the growing direction in the molecular aggregate formedby a sequential coupling of the molecular structure and the extension.In addition, spacings among the molecular structures constituting themolecular aggregate, can be controlled by controlling the length of acrosslinking agent. Here, the number of bonding residues existing insidethe crosslinking agent is not particularly limited so far as being 2 ormore, but is preferably 2 or more but 10 or less, and further preferably2 or more but 4 or less (hereafter, the same). In addition, if thecrosslinking agent of a medium shows a liquid crystal property, it ispossible to impart directionality to a nano-wire by applying an externalfield such as an electric field and a magnetic field.

(15) Another invention according to the present application is “a methodof producing a molecular device including: the use of a molecularstructure having a plurality of bonding residues in the molecule, asensitizer, and a crosslinking agent containing a plurality of bondingresidues; the energy imparting step of imparting energy to thesensitizer; one or both of an energy transfer process and an electrontransfer process, which are stages including energy transfer or electrontransfer from the energy-imparted sensitizer to one or both of thebonding residues of the structure and the bonding residues of thecrosslinking agent; and the step of crosslinking the bonding residues inthe molecule of the molecular structure with the crosslinking agent bythe energy transfer process or the electron-imparting stage, to obtain amolecular aggregate having a plurality of molecular structuresthree-dimensionally combined through the crosslinking agent”. Themolecular aggregate obtained through such steps includes a nano-wire,for instance. One example of the nano-wire includes one having themolecular structures regularly disposed.

(16) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (15), wherein the energy imparted to the sensitizer in theenergy imparting step is an energy originating in any one of anelectron, an ion and an electromagnetic wave, or a combination thereof”.

(17) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (15), wherein the energy imparted to the sensitizer in theenergy imparting step is a light energy due to an ultra-violet ray, avisible ray and an infrared ray”.

(18) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (15), characterized in that the energy imparted to thesensitizer in the energy imparting step is a light energy due to anultra-violet ray, a visible ray and an infrared ray; and that the energytransfers from the energy-imparted sensitizer to the bonding residuesthrough an energy transfer process”.

(19) Another invention according to the present application is “Themethod of producing a molecular device according to the item (18),wherein the energy imparted to the sensitizer in the energy impartingstep is a light energy due to an ultra-violet ray, a visible ray and aninfrared ray, and the energy transfer in the energy transfer process isa triplet energy transfer process”.

(20) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (19), wherein the bonding residue is an optically bondingresidue”.

(21) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (19), wherein the bonding residue has at least one of one orboth of a double bond and a triple bond”.

(22) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (19), wherein the bonding residue is one of a cinnamic acidgroup, an α-cyano cinnamic acid group, a coumarin group, a chalconegroup, a cinnamylidene acetate group, a p-phenylene diacrylate group, anacetylene group, a diacetylene group, a diphenyl acetylene group and ananthracene group”.

(23) Another invention according to the present application is “a methodof producing a molecular device including: the use of a molecularstructure having a higher atomic density in the periphery than in theinterior and having bonding residues in the periphery, and aphotosensitizer molecule that is included inside the molecularstructure, or is covalently bonded, ionically bonded, coordinatelybonded, metallically bonded or hydrogen bonded with the molecularstructure; and a shell-forming step of joining the bonding residues byphotoirradiation, to obtain the molecular structure having the shellstructure”.

(24) Another invention according to the present application is “themethod of producing a molecular device according to the item (23),characterized in that the molecular structure is constituted by askeleton portion having a skeleton structure and a terminal portionwhich is arranged in the outer shell of the skeleton portion, has ahigher atomic density than that of the skeleton portion, and has aplurality of bonding residues; and that in the shell-forming step, thebonding residues in the terminal portion of the molecular structure arecombined by irradiating the photosensitizer molecule with light”.

(25) Another invention according to the present application is “themethod of producing a molecular device according to the item (23),characterized in that the plurality of bonding residues existing in theterminal portion are combined to obtain the molecular structure havingthe shell structure”.

(26) Another invention according to the present application is “themethod of producing a molecular device according to the item (23),characterized in that the method further includes the use of themolecule of a crosslinking agent, makes the molecule of the crosslinkingagent crosslink with the bonding residues, and three-dimensionallycombines a plurality of molecular structures through the crosslinkablemolecule”.

(27) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(23) to (26), wherein the bonding residue is an optically bondingresidue”.

(28) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(23) to (26), wherein the bonding residue has at least one of one orboth of a double bond and a triple bond”.

(29) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(23) to (26), wherein the bonding residue is any one of a cinnamic acidgroup, an α-cyano cinnamic acid group, a coumarin group, a chalconegroup, a cinnamylidene acetate group, a p-phenylene diacrylate group, anacetylene group, a diacetylene group, a diphenyl acetylene group and ananthracene group”.

(30) Another invention according to the present application is “themethod of producing a molecular device according to any one of the items(12) to (29), wherein the molecular structure is a dendrimer”.

(31) Another invention according to the present application is “themethod of producing a molecular device according to the item (30),wherein the dendrimer is expressed by the following formula (I) or(II)”:

wherein n represents an integer of 10 or less, or

wherein n represents an integer of 10 or less and R represents a linkagegroup.

Here, in the general formulas (I) and (II), n is an integer of 1 to 10,preferably of 2 to 10, and further preferably of 3 to 8. In addition, R(a coupling group) in the general formula (II) includes, for instance,an alkenyl group with C₁ to C₁₀ and an alkynyl group with C₂ to C₁₀, butis not particularly limited so far as being a coupling group used forthe dendrimer.

(32) Another invention according to the present application is “themethod of producing a molecular device according to the item (31),wherein R in the general formula (II) is an alkenyl group with C₁ to C₁₀or an alkynyl group with C₂ to C₁₀”.

(33) Another invention according to the present application is “themethod of producing a molecular device according to the item (31) or(32), wherein each n in the general formulas (I) and (II) is an integerof 2 to 10”.

(34) Another invention according to the present application is “amolecular structure having a shell structure obtained by: using amolecular structure constituted by a skeleton portion having a skeletonstructure, and a terminal portion which is arranged in the outer shellof the skeleton portion, has a higher atomic density than that of theskeleton portion and has a plurality of bonding residues, and aphotosensitizer molecule included inside the molecular structure; andjoining the bonding residues in the terminal portion by taking advantageof the spectral sensitization of the photosensitizer molecule irradiatedwith light”.

(35) Another invention according to the present application is “amolecular aggregate obtained by: using a molecular structure constitutedby a skeleton portion having a skeleton structure, and a terminalportion which is arranged in the outer shell of the skeleton portion,has a higher atomic density than that of the skeleton portion and has aplurality of bonding residues, a photosensitizing molecule containedinside the molecular structure, and the molecule of a crosslinkingagent; and crosslinking the bonding residues with the molecule of thecrosslinking agent through irradiating the photosensitizer molecule withlight to combine a plurality of molecular structures”.

(36) Another invention according to the present application is “amolecular device including the molecular structure having the shellstructure according to the item (34), or the molecular aggregateaccording to the item (35)”.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a molecular structure (anano-particle) having a shell structure;

FIG. 2 is a conceptual diagram of a nano-particle according to thepresent invention;

FIG. 3 is a conceptual diagram of a molecular aggregate (a nano-wire);

FIG. 4 is a conceptual diagram of a nano-wire according to the presentinvention;

FIG. 5 is a conceptual diagram of a photoconductive nano-wire by arod-shaped dendrimer;

FIG. 6 is a conceptual diagram showing one example of a single electrontransistor (SET);

FIG. 7 is a conceptual diagram showing one example of a T-typeoptoelectronic device (TOED); and

FIG. 8 shows one example of a dendrimer.

BEST MODE FOR CARRYING OUT THE INVENTION

A method of producing a molecular structure, a molecular aggregate and amolecular device according to the present invention will be nowdescribed in detail below.

A method of producing a molecular device according to the presentinvention uses a molecular structure which has a higher atomic densityin the periphery than in the interior and has a bonding residue in theperiphery. According to one example according to the present invention,a molecular structure or a molecular aggregate is produced bycrosslinking the bonding residue existing in the periphery of themolecular structure, within the molecular structure or between themolecular structures.

In another example according to the present invention, an energy isimparted to a solution or a solid containing a molecular structure and asensitizer through the light having wavelengths absorbed by the abovedescribed sensitizer, or the like. The solution or the solid may containa binding resin (a binder) and other secondary materials. In the presentinvention, a molecular structure having a shell structure or a molecularaggregate having the molecular structures three-dimensionally combinedis produced by using a phenomenon that light energy is absorbed in asensitizer; the energy absorbed by the sensitizer transmits to amolecular structure such as a dendrimer; alternatively an electron, anion or a radical migrates; and the energy causes a bonding reaction or acrosslinking reaction of the bonding residue existing in the molecularstructure.

Each molecular structure preferably functions as a molecular elementhaving various functions such as an optical memory effect. Then, amolecular aggregate (or a molecular device) having various functions canbe produced by one-dimensionally, two-dimensionally andthree-dimensionally combining the molecular structures one after anotherinto a linear shape, a grid shape or a radical shape. The position wherethe molecular structure is combined, can be controlled by controllingthe position of the bonding residue in the molecular structure, whichleads to a control of the growing direction in the molecular aggregateformed by a sequential coupling of the molecular structure and theextension. In addition, spacings among the molecular structurescomposing the molecular aggregate can be controlled by controlling thelength of a crosslinking agent.

Here, a molecular structure means a molecule in which a plurality ofparts having different functions exist in different portions of onemolecule such as a residue part and a central part. The molecularstructure includes the one constituted by a skeleton portion having askeleton structure, and a terminal portion which is arranged in theouter shell (outside) of the skeleton portion, has a higher atomicdensity than that of the skeleton portion, and has bonding residues. Themolecular structure preferably has a plurality of (two or more) bondingresidues. The bonding residue is preferably an optically bondingresidue. The molecular structure is preferably a dendrimer. Thedendrimer is preferably one shown in the above described general formula(I) or in the above described general formula (II). Here, n in thegeneral formulas (I) and (II is an integer of 1 to 10, preferably of 2to 10, and further preferably of 3 to 8. In addition, R in the generalformula (II) includes an alkenyl group with C₁ to C₁₀ and an alkynylgroup with C₂ to C₁₀, but is not particularly limited so far as being acoupling group used for the dendrimer.

The molecular structure is preferably a molecule which can contain asensitizer, or a molecule which is covalently bonded, ionically bonded,coordinately bonded, metallically bonded or hydrogen bonded with asensitizer, and particularly preferably a dendrimer (a hyper-branchedpolymer) having an optical functionality and an electronicfunctionality, but is not limited in particular so far as being acompound having a bonding residue. The molecule of the dendrimer has ananometric space in itself, and has an uniqueness capable of including aforeign molecule or a foreign atom in the space. Details onencapsulation phenomenon of the dendrimer are described in Science, 266,1226 (1994) by J. Jansen, E. Berg and E. Meijer; and in Nature, 389 and368 (1997), by A. Cooper, J. Londono, G. Wignall, J. McClain, E.Samulski, J. Lin, A. Dobrynin, M. Rubinstein, A. Burke, J. Frechet andJ. DeSimone; which are both scientific magazines.

A bonding residue (an photocrosslinkable residue) in a molecularstructure includes (a) an aliphatic residue having an unsaturated doublebond, such as a vinyl group, an acrylate group and a methacrylate group,(b) an aromatic residue having an unsaturated double bond, such as acinnamic acid group, an α-cyano cinnamic acid group, a coumarin group, achalcone group, a cinnamylidene acetate group, a p-phenylene diacrylategroup, a distyrylpyrazine group and an anthracene group, (c) analiphatic residue having an unsaturated triple bond, such as anacetylene group and a diacetylene group, and (d) an aromatic residuehaving an unsaturated triple bond, such as a diphenyl-acetylene group, aphenyl azide group and a dypyridyl diacetylene group. In addition, thederivative materials thereof are also acceptable. The residues in (a)require a radical photopolymerization initiator in order to show aradical polymerization reaction. On the other hand, thephotocrosslinkable residues in (b) to (d) do not require such aphotopolymerization initiator as is required in the case of (a), becausethey show a photoaddition reaction according to the Woodward-Hoffmann'slaw, such as a [2π-2π] photodimerization reaction. Details on thesephotosensitive residues are described in “Photosensitive Polymer” ofKodansha scientific (1977), by Nagamatsu Mototaro and Inui Hideo.

As for the irradiation light used when preparing a crosslinked body bythe light, an x-ray, an electron beam, an ultra-violet ray, a visibleray or an infrared-ray (a heat ray) is used. Among them, the ultravioletray or the visible ray is particularly preferable. A usable light sourceincludes an extra-high pressure mercury lamp, a low pressure mercurylamp, a xenon lamp, a mercury xenon lamp, a halogen lamp, a fluorescentlamp, a gas laser, a liquid laser, and a solid state laser. In addition,the surface plasmon radiation of the light emitted from these lightsources may be used.

In order to combine (crosslink) bonding residues mutually or molecularstructures each other, the bonding residue may be directly excited toinduce an intramolecular bonding or an intermolecular bonding, andintramolecular crosslinking and intermolecular crosslinking may beformed with the use of a crosslinking agent. In order to combine eachmolecular structure, a bonding residue (a photocrosslinkable residue)may be directly excited to induce an photocrosslinking reaction, but inorder to more efficiently and more selectively cause coupling inside ananometric region in the molecular structure and coupling betweenmolecular structures, “spectrum sensitization” is preferably used. Bythus using spectrum sensitization, as shown in FIG. 2 and FIG. 4, anano-particle and nano-wire of the molecular structure becomes easilyproduced. In the preparation step, a sensitizer, so to speak, ispreferably added which is a molecule capable of spectrally sensitizing abonding residue (a photocrosslinkable residue) by using the uniquenessof a dendrimer molecule capable of including a foreign molecule or aforeign atom inside itself, as described above. The detail of thesensitizer is described in “Sensitizer”, Kodansha scientific, (1987) byTokumaru Katsuyuki and Okawara Makoto. The mechanism of spectrumsensitization includes a photoelectron transfer and a light energytransfer. The light energy transfer is broadly divided into two typesaccording to a photoexcited state. One is a singlet energy transfer(Forster's type) based on a dipole-dipole interaction, and the other isa triplet energy transfer (Dexter's type) based on an electron exchangeinteraction. The detail of the light energy transfer is described inModern Molecular Photochemistry, University Science Books (1991) by N.Turro. The transfer distance of the photoelectron transfer is about 0.4to 2.0 nm, and the transfer distances of the singlet and triplet energytransfers are respectively about 1.0 to 10 nm and 0.3 to 1.0 nm. Amongthese spectrum sensitization mechanisms, in the present invention, thetriplet energy transfer for spectrum sensitization in a nanometricregion is preferably used to optically combine the optically and/orelectronically functional molecular structures.

In the present specification, crosslinking means combining two or moremolecular structures by using a crosslinking agent, and besides,combining bonding residues in the same molecular structure or betweenthe molecular structures without using the crosslinking agent. In thepresent invention, a crosslinking agent means a molecular for joiningthe bonding residues in a molecular structure mutually. The crosslinkingagent includes, for instance, butadiene, pentadiene and a hydrocarbonhaving the bonding residue in the molecular structure. The crosslinkingagent combines molecular structures mutually while controlling thespacing, by controlling the length of itself, and provides a molecularaggregate having regularity.

In a method of producing a molecular device according to the presentinvention, a molecular structure or molecular aggregate having a shellstructure described bellow may be obtained as an intermediate product.

The molecular structure having the shell structure (hereafter alsocalled a “nano-particle”) is produced, for instance, by crosslinking thebonding residues of a molecular structure which has a higher atomicdensity in the periphery than in the interior and has the bondingresidues in the periphery, into the shell. More specifically, themolecular structure having the shell structure is a substance having thebonding residues existing in the periphery of the molecular structurecombined and form a shell-like state. In particular, when the molecularstructure has not so high a density, and a large intermolecular distancebetween the molecular structures, it mainly produces a nano-particle.

FIG. 1 shows a conceptual diagram of a nano-particle. FIG. 1 (a) shows amolecular structure (a dendrimer) 1. When the molecular structure shownin FIG. 1 (a) is irradiated with light, the bonding residue 6 inside themolecular structure is crosslinked (combined) to form crosslinking partshown in FIG. 1 (b)-2. Thus, the nano-particle 4 is formed which is themolecular structure having the shell structure. The crosslinkingreaction can be performed in a solvent such as dichloromethane, and maybe performed in a solid phase as well.

One example of a nano-particle will be described with reference to FIG.2. A molecular structure 1 such as a dendrimer has a sensitizer 3 in theperiphery and the interior (FIG. 2 (a)). The sensitizer absorbs energyby photoirradiation. The absorbed energy by the sensitizer istransferred to the molecular structure as shown by numeral 10. Then, inthe molecular structure 1, bonding residues are mutually combined(crosslinked) by the transferred energy to form a crosslinking reactionpart 9 (FIG. 2 (b)). Thus, the crosslinking reaction part forms a shelland a consequent nano-particle.

A molecular assembly having a plurality of molecular structurescombined, (hereafter also called a nano-wire) is produced, for instance,by crosslinking the connective residues in a molecular structure whichhas a higher atomic density in the periphery than in the interior andhas the connective residues in the periphery, and combining theconnective residues of the adjacent molecular structures. The molecularstructure according to the present invention has a plurality of bondingresidues, for instance, inside the molecular. Then, when crosslinkingproceeds, a plurality of molecular structures are radially assembled. Inparticular, when the molecular structure has a high density, and a smallintermolecular distance between the molecular structures, it mainlyproduces a nano-wire.

For reference, a conceptual diagram of a nano-wire is shown in FIG. 3.As for one example of producing a molecular aggregate, as shown in FIG.3 (a), the molecular structure 1 having the bonding residues 6 in theperiphery is irradiated with light. Then, as shown in FIG. 3(b), acrosslinkable residue in the molecular structure 1 and a crosslinkingagent 3 are crosslinked to obtain a molecular aggregate 5.

In addition, when the crosslinking proceeds by an added crosslinkingagent, the bonding residue in the molecular structure causes acrosslinking reaction with the crosslinking agent. In the above step, bycontrolling the length of the crosslinking agent, the molecularstructures can assemble keeping distances among the molecular structurescontrolled, to form a molecular aggregate.

A molecular aggregate according to the present invention, (hereafteralso called a nano-wire) is produced, for instance, by crosslinking thebonding residues in a molecular structure which has a higher atomicdensity in the periphery than in the interior and has the bondingresidues in the periphery, and joining the bonding residues of theadjacent molecular structures. Another example of a nano-wire isdescribed with reference to FIG. 4. As shown in FIG. 4 (a), themolecular structure 1 having bonding residues in the periphery and thesensitizer 3 are irradiated with light. The sensitizer absorbs energydue to photoirradiation. The absorbed energy by the sensitizer istransferred to the molecular structure as shown by numeral 10. Then, asshown in FIG. 4 (b), the crosslinkable residue and the crosslinkingagent 5 in the molecular structure 1 are crosslinked to form thecrosslinking reaction part 9 and provide the molecular aggregate 7 (FIG.4 (b)).

In addition, when the crosslinking proceeds by addition of acrosslinking agent, the bonding residue in the molecular structurecauses a crosslinking reaction with the crosslinking agent, and themolecular structures can assemble keeping distances among the molecularstructures controlled, to form a molecular aggregate as well.

A molecule device includes, for instance, devices with the use of theabove described nano-particle or nano-wire. A molecular structure hasvarious functions. Accordingly, by controlling the aggregated form ofthe molecular structures in a molecule-level or a nano-level, amolecular device can be obtained. For instance, by crosslinking thebonding residues in the molecular structures while controlling thepositions, the three-dimensional structure of a molecular aggregate canbe controlled.

FIG. 5 shows a conceptual diagram of a photoconductive nano-wire using arod-shaped dendrimer, which is one example of a molecular deviceaccording to the present invention.

FIG. 5 (a) shows a rod-shaped dendrimer molecule of which thecircumference is modified with bonding residues. When a solutioncontaining the dendrimer is irradiated with light, the bonding residuesin the dendrimer are combined, and a photoconductive nano-wire which isa molecular device as shown in FIG. 5 (b), can be obtained. Thephotoconductive nano-wire has approximately equal formation rates of afree electron and a positive hole, so that it behaves like an intrinsicsemiconductor. More specifically, by using such a molecular device, asemiconductor element having the shape controlled in a nanometric levelcan be obtained. The really obtained photoconductive nano-wire had theelectron mobility of about 1 cm²/V in the axial direction and about0.001 cm²/V in the radial direction.

Furthermore, when the void of the photoconductive nano-wire was dopedwith iodine, the electroconductivity of the photoconductive nano-wirewas drastically improved.

A molecular structure has various functions. Accordingly, for instance,by combining such molecular structures one after another toward apreferable direction through a crosslinking agent, a molecular devicecan be obtained. The crosslinked part can be an information transferpath when the molecular structure having functionality transfersinformation such as an electric signal. By such a method, a moleculardevice can be obtained which functions as an information transfer systemas if a neuron extends an axon to other neurons. In addition, when amethod of producing the molecular device is applied between electrodes,molecular structures are combined, and the molecular device capable oftransmitting information can be obtained. By using the molecular device,a functional product can be obtained which uses the molecular deviceconsisting of combined molecular elements (molecular structures) havingfunctionality. FIG. 6 is a conceptual diagram showing one example of asingle electron transistor (SET) of a molecular device which can beproduced with such a production method. In FIG. 6, numeric 1 expresses amolecular structure which can function as a molecular element, numeric 5expresses a crosslinking agent, numeric 9 expresses a crosslinkingreaction part, and numeric 11 expresses an electrode. A SET shown inFIG. 6 was produced as described below. At first, an electrode 11 havinga spacing of about 50 nm was prepared. The spacing of the electrode 11can be controlled to about 10 nm to 1 μm. Then, a dendrimer havingbonding residues at both poles (in opposed positions), and a solutioncontaining a sensitizer and a crosslinking agent were prepared so as tocombine the electrodes. Then, the solution containing the dendrimer wasirradiated with light. Then, a molecular device (SET) as shown in FIG. 6could be obtained. When voltage was applied on the molecular device, aphenomenon showing a stepped current-voltage characteristic (a Coulombblockade phenomenon) was observed. From the result, it was found thatthe crosslinking agents combined mutually by photoirradiation functionsas a tunnel layer.

FIG. 7 is a conceptual diagram showing one example of a T-typeoptoelectronic element (TOED) which is another molecular deviceaccording to the present invention.

One example of methods of producing TOED is now described below. Atfirst, a substrate made of mica was prepared. The substrate may be aninsulator such as gold, copper, platinum and mica. Subsequently, thesubstrate was immersed into a solution containing four types ofmolecular structures A, B, C and D, and a sensitizer. In the abovesolution, a crosslinking agent may be contained. The molecular structureA has such a bonding residue in the first position as to be combinedwith a certain bonding residue in the molecular structure B. Themolecular structure A may have such a bonding residue in the tenthposition as to be combined with a certain bonding residue in themolecular structure C. (In this case, the obtained molecular device isnot a TOED but a continuum of a T-type optoelectronics.) The molecularstructure B has each bonding residue in the first position, the fifthposition and the tenth position as to be combined with each certainbonding residue respectively in the molecular structures C, D and A. Themolecular structure B may have such a bonding residue in the 15thposition as to be combined with a certain bonding residue in themolecular structure D. (In this case, the obtained molecular device isnot a TOED but a continuum of a T-type optoelectronics.)

When the solution was irradiated with light, a molecular device wasformed on the substrate.

When an optical signal was input in the molecular structure A out of themolecular devices, an output was observed from the molecular structure Bafter 30 picoseconds.

On the other hand, when the molecular structure D was oxidized and thenan optical signal was input in the molecular structure A, the output wasnot obtained from the molecular structure B.

In addition, by using a molecular device according to the presentinvention, a molecular integrated circuit, for instance, described inJapanese Patent Laid-Open No. 2001-44413, can be manufactured. Themolecular integrated circuit with the use of the molecular deviceaccording to the present invention, can be used as a NAND circuit, a NORcircuit, an inverter circuit, a random access memory cell and a readonly memory cell, as in the case of a molecular integrated circuitdescribed in Japanese Patent Laid-Open No. 2001-44413. In the presentinvention, because a molecular device can be constructed by using aphotosensitization reaction, molecular devices can be more precisely andspeedily produced.

PRODUCTION EXAMPLE 1 Method of Synthesizing Dendrimer Having CinnamicAcid Amide Residue in Terminal

Into a dichloromethane solution of a poly(propyleneimine) dendrimer (1.0g, 3.2 mmol, made by Aldrich Corporation) of the first generation (n=1in FIG. 8) containing a catalytic quantity of triethylamine, a solutionof trans-cinnamyl chloride (0.63 g, 3.7 mmol, made by AldrichCorporation) was dropped, and the resultant solution was stirred at 0°C. for one hour and then at room temperature for 40 hours. This reactionliquid was diluted with dichloromethane, was cleaned sequentially withion-exchange water, an aqueous solution of sodium carbonate and anaqueous solution of sodium chloride, and was dried with magnesiumsulfate. After filtration, dichloromethane was removed by an evaporator.The crude product was dialyzed and reprecipitated repetitively for threetimes, and was dried under a reduced pressure. Then, a white solid wasobtained.

Each poly(propyleneimine) dendrimer of the third generation and thefifth generation (respectively n=3 and 5 in FIG. 8) was also synthesizedand refined with a similar method to the above described method.

Various physical properties of thus synthesized dendrimer are shown inTable 1 and Table 2. TABLE 1 A plurality of physical properties ofsynthesized dendrimer Results of measurement on weight average molecularweight and molecular weight distribution by size exclusionchromatography Weight average Molecular weight Calculated Dendrimermolecular weight distribution value First generation 905 1.02 837 Thirdgeneration 4103 1.01 3768 Fifth generation 16084 1.02 15497

TABLE 2 Results of measurement of melting point by differential scanningcalorimetry First Third Fifth Dendrimer generation generation generationMelting point (° C.) 150 103 93

EXAMPLE 1 Production of Nano-Particle EXAMPLE 1-1

With the use of polypropylene imine dendrimer of the first generation(n=1) having residues of cinnamamide in the periphery of the molecularas shown in FIG. 8, the following experiment was carried out. Aplurality of dichloromethane dilute solutions containing 3.0×10−5(mol/L) of the dendrimer having cinnamamide by molar unit of cinnamamidein the dendrimer were prepared and were put in quartz cells having adimension of 1.0 cm per side. The light having a wavelength of 313 nmwhich was taken out from a mercury xenon lamp having an output of 200 W,irradiated the previously prepared solution. With the photoirradiation,the absorption bands around 280 nm originated in the residue ofcinnamamide decreased. The absorption spectrum after thephotoirradiation was measured, and the abundance ratio of each transisomer, cis isomer and associated body of the cinnamamide residue wascalculated. The result is shown in Table 3. Here, the associated bodymeans a product in which the cinnamamide residues are mutually combined.

EXAMPLE 1-2

As in the Example 1-1 except that the polypropylene imine dendrimer ofthe third generation (n=3 in FIG. 8) was employed, an experiment wascarried out. The result is shown in Table 3.

EXAMPLE 1-3

As in the Example 1-1 except that the polypropylene imine dendrimer ofthe fifth generation (n=5 in FIG. 8) was employed, an experiment wascarried out. The result is shown in Table 3. TABLE 3 Results ofmeasurement of absorption spectrum after photoirradiation in dilutesolution of propylene imine dendrimer Quantity of Trans Cis exposureenergy isomer isomer Associated (J/cm²) (%) (%) body (%) First 0.4 86 113 generation 2.0 56 39 5 10 40 48 12 20 30 53 17 30 21 59 20 Third 0.487 9 4 generation 2.0 62 25 13 10 40 34 26 20 24 39 37 30 19 40 41 Fifth0.4 83 l0 7 generation 2.0 66 17 17 10 46 21 33 20 34 24 42 30 24 26 50

From the Table 3, it was found that in the bonding dendrimer moleculeassociated with the present invention, as the quantity of exposureenergy in a dilute solution increases, the ratio of the trans isomer ofthe cinnamamide residue decreases; whereas the ratio of the cis isomerand the associated body increases. It was found that particularly theincreasing ratio of the associated body strongly depends on thegeneration of the dendrimer molecule, and the dendrimer of the fifthgeneration effectively forms the associated body. A fully irradiatedsolution with light was subjected to gel permeation chromatography, andthe retention times before and after the photoirradiation were measuredto prove that they were not changed. It means that the molecular weightof the dendrimer was maintained before and after the photoirradiation.Accordingly, in the solution of the dilute concentration, a couplingreaction occurred not between molecules but inside the dendrimermolecule, which means that a nano-particle was produced in the dilutesolution. The nano-particle is considered to form in such a manner thatthe cinnamyl residues in a polypropylene imine dendrimer werephotoexcitated, and sequentially caused dimerization (intramolecularcoupling) with the adjacent cinnamyl residues. Because with the increaseof the generation of a polypropylene imine dendrimer, the density of thecinnamyl residue increases, the ratio of the associated body consistingof mutually combined cinnamyl residues also increases with the increaseof the generation of the dendrimer.

COMPARATIVE EXAMPLE 1

Instead of the bonding dendrimer used in the above described Example1-1, cinnamamide was employed and the dilute solution was prepared. Thenthe solution was irradiated with light as in the Example 1. The resultis shown in Table 4. TABLE 4 Results of measurement of absorptionspectrum after photoirradiation in a dilute cinnamamide solutionQuantity of Trans Cis exposure energy isomer isomer Associated (J/cm²)(%) (%) body (%) Cinnamamide 0.4 82 16 2 2.0 40 56 4 10 23 73 4 20 23 725 30 21 74 5

The comparison of the above described Table 3 with the Table 4 makes itclear that the formation rate of the associated body of cinnamamide isgreatly different from that of the crosslinkable dendrimer, and isextremely low.

EXAMPLE 2 Production of Nano-Particle in Solid Layer EXAMPLE 2-1

With the use of a polypropylene imine dendrimer of the first generation(n=1), the following experiment was carried out. So as to have the ratioof a cinnamamide unit to a methyl methacrylate monomer unit in adendrimer controlled to 1:10, a solution was prepared which contains thecrosslinkable dendrimer diluted and dispersed in poly(methylmethacrylate). Each aliquot of the dichloromethane solution thusprepared was applied onto a glass substrate with a spin coating method.The solution was dried and solidified, then the light having thewavelength of 313 nm was taken out from a mercury xenon lamp having theoutput of 200 W, and the glass substrate was irradiated with it. Withthe photoirradiation, the absorption bands around 280 nm originated inthe residue of cinnamamide was decreased. The absorption spectrum afterthe photoirradiation was measured, and the abundance ratio of each transisomer, cis isomer and associated body of the cinnamamide residue wascalculated. The result is shown in Table 5.

EXAMPLE 2-2

As in the Example 2-1 except that the polypropylene imine dendrimer ofthe third generation (n=3 in FIG. 8) was employed, an experiment wascarried out. The result is shown in Table 5.

EXAMPLE 2-3

As in the Example 2-1 except that the polypropylene imine dendrimer ofthe fifth generation (n=5 in FIG. 8) was employed, an experiment wascarried out. The result is shown in Table 5. TABLE 5 Results ofmeasurement of absorption spectrum after photoirradiation in solidlayers of propylene imine dendrimer Quantity of Trans Cis Photocross-exposure energy isomer isomer linked (J/cm²) (%) (%) body (%) First 0.290 9 1 generation 1.0 72 21 7 5.0 46 28 26 9.0 34 29 37 15 27 28 45Third 0.2 89 7 4 generation 1.0 67 17 16 5.0 36 29 35 9.0 24 31 45 15 1632 52 Fifth 0.2 88 6 6 generation 1.0 57 20 23 5.0 28 27 45 9.0 18 27 5515 12 28 60

It was found from Table 5 that as for the crosslinkable dendrimermolecule associated with the present invention, the increasing ratio ofthe associated body of cinnamyl residues strongly depends on thegeneration of the dendrimer molecule in a solid as well, as seen in aphotochemical reaction behavior in a dilute solution in the abovedescribed Example 1, and the dendrimer of the fifth-generationeffectively forms a photocrosslinked body. In addition, it was judgedfrom ultraviolet-visible absorption spectrum measurement that when thethin film of a dendrimer/poly (methyl methacrylate) after beingirradiated with light is immersed in dichloromethane of a solvent usedin a spin coating, the film is removed from a glass substrate.

COMPARATIVE EXAMPLE 2

Instead of the crosslinkable dendrimer used in the above describedExample 2, cinnamamide was employed and diluted in poly(methylmethacrylate) to make thin films. Then the thin films were irradiatedwith light as in the Example 2. The results are shown in Table 6. TABLE6 Results of measurement of absorption spectrum after photoirradiationin solid layer of cinnamamide Quantity of Trans Cis exposure energyisomer isomer Associated (J/cm²) (%) (%) body (%) Cinnamamide 0.2 80 191 1.0 54 45 1 5.0 40 55 5 9.0 38 57 5 15 31 64 5

The comparison of the above described Table 5 with the Table 6 makes itclear that in the photochemical behavior in a solid as well as in adilute solution, the formation rate of the associated body ofcinnamamide is greatly different from that of a crosslinkable dendrimer,and is extremely low.

EXAMPLE 3

Except that a polypropylene imine dendrimer molecule was solely usedinstead of the polypropylene imine dendrimer molecule diluted anddispersed in poly (methyl methacrylate), a similar experiment to theExample 2-1, the Example 2-2 and the Example 2-3 was performed. Though aglass substrate was immersed in dichloromethane, a film remained on theglass substrate. This occurred because in the present example, thepolypropylene imine dendrimer molecular became a macromolecule insolublein dichloromethane.

It is clear from the Example 2 and the Example 3 that in adendrimer/poly (methyl methacrylate) diluted film a cinnamyl residue isa core of an intramolecular bonding inside one molecule of thedendrimer, and that in a dendrimer-rich thin film, an intermolecularbonding among dendrimer proceeds. In addition, it is clear that in asolid as well, a nano-particle and a nano-wire can be produced.

EXAMPLE 4-1

In a dichloromethane solution of the polypropylene imine dendrimer ofthe first-generation (n=1 in general formula (1) having a cinnamamideresidue in the periphery of the molecule,4,4′-bis(dimethylamino)benzophenone was each mixed as a sensitizer, andthe solute was reprecipitated in a surplus quantity of hexane. Theprecipitate was dialyzed with dichloromethane and was reprecipitatedagain.

The dichloromethane solution of the polypropylene imine dendrimer of thefirst generation which includes 4,4′-bis(dimethylamino)benzophenone wasirradiated with the light having the wavelength of 365 nm which wastaken out from a mercury xenon lamp with an output of 200 W. In theabove step, the temperature of the solution was room temperature.

A cinnamamide residue does not absorb light of 365 nm, but4,4′-bis(dimethylamino)benzophenone has an absorption band in thevicinity of 365 nm. It was found from the result of ultraviolet-visibleabsorption spectrum measurement that the number of molecules of4,4′-Bis(dimethylamino)benzophenone included in the dendrimer was nilfor the first generation. The dichloromethane solution containing thedendrimer, which was prepared in the above described method, wasthoroughly irradiated with the light of 365 nm, but no change wasobserved in ultraviolet-visible absorption spectra.

EXAMPLE 4-2

Except that the polypropylene imine dendrimer of the third generation(n=3 in general formula (1)) was employed, a similar experiment to theExample 4-1 was carried out to produce a molecular aggregate.

As a result of ultraviolet-visible absorption spectral measurement, itwas found that the number of molecules of4,4′-bis(dimethylamino)benzophenone included in the dendrimer was threefor the third generation.

EXAMPLE 4-3

Except that the polypropylene imine dendrimer of the fifth generation(n=5 in general formula (1)) was employed, a similar experiment to theExample 4-1 was carried out to produce a molecular aggregate.

As a result of ultraviolet-visible absorption spectrum measurement, itwas found that the number of molecules of4,4′-bis(dimethylamino)benzophenone included in the dendrimer was eightfor the fifth generation.

EXAMPLE 5-1

So as to make the ratio of a cinnamamide unit to a methyl methacrylatemonomer unit in a dendrimer controlled to 1:10, a solution was preparedwhich has the photocrosslinkable dendrimer molecules (the thirdgeneration polypropylene imine dendrimer) including4,4′-Bis(dimethylamino)benzophenone diluted and dispersed in poly(methylmethacrylate).

The poly(methyl methacrylate) solution prepared in such a method wasapplied onto a glass substrate with a spin coat method. The glasssubstrate after being coated with the solution, was dried at roomtemperature to form a solid containing the dendrimer thereon.

The light having the wavelength of 365 nm was taken out from a mercuryxenon lamp having the output of 200 W, and the glass substrate wasirradiated with the light. With progress of the photoirradiation, theabsorption bands around 280 nm originating from a cinnamamide residuedecreased. The absorption spectrum after the photoirradiation wasmeasured, and the abundance ratio of each trans isomer, cis isomer andphotocrosslinked body of the cinnamamide residue was calculated. Theresult is shown in Table 7.

EXAMPLE 5-2

Except that the polypropylene imine dendrimer of the fifth generationwas employed, a similar experiment to the Example 5-1 was carried out toproduce a molecular aggregate. As in the Example 5-1, the absorptionspectrum after the photoirradiation was measured, and the abundanceratio of each trans isomer, cis isomer and photocrosslinked body of thecinnamamide residue was calculated. The result is shown in Table 7.TABLE 7 Isomeric ratios in the third and fifth generation dendrimersafter photoirradiation Quantity of Trans Cis Photocross- exposure energyisomer isomer linked (J/cm²) (%) (%) body (%) Third 0.1 76 13 11generation 0.4 54 19 27 1.0 32 22 46 2.0 18 24 58 3.0 13 24 63 Fifth 0.181 14 5 generation 0.4 63 17 20 1.0 44 20 36 2.0 27 24 49 3.0 20 26 54

From a result shown in Table 7, it is clear that with photoirradiation,the formation ratio of the trans isomer of the cinnamamide residuedecreased, and the formation ratios of the cis isomer and thephotcrosslinked body increased.

In addition, the comparison result of the formation ratios of thephotocrosslinked body of cinnamamide between the dendrimers of the thirdgeneration and of the fifth generation, made it clear that the ratio inthe dendrimer of the third generation is higher than that in thedendrimer of the fifth-generation. A dendrimer including4,4′-bis(dimethylamino)benzophenone could form a photocrosslinked bodyby the low exposure energy of 3.0 J/cm² in the wavelength of 365 nm. Theexposure energy of 3.0 J/cm² is lower than that in producing aphotocrosslinked body by directly exciting a cinnamamide residue withthe light having the wavelength of 313 nm. This is considered to happenbecause a sensitizer absorbs light, and due to the light energy absorbedby the sensitizer, connective residues have been effectively combined(crosslinked). Thus, it can be said that the present invention, in spiteof using an exposure light of low energy, has succeeded in forming astructure of single molecular highly sensitively by photocrosslinking.

EXAMPLE 5

A dendrimer/poly(methyl methacrylate) thin-film after photoirradiationwas immersed in dichloromethane which is a solvent used for a spincoating. As a result, it was judged from ultraviolet-visible absorptionspectrum measurement that the film is removed from the surface of theglass substrate. From the fact, it is considered that when a dendrimerdilute solution is irradiated with light, a polymer is not formed. Thisis considered to happen because the bonding residues in the dendrimerwere combined by photoirradiation to mainly form nano-particles.

EXAMPLE 6

A thin film containing only photocrosslinkable dendrimers was fullyirradiated with the light of 365 nm, and was immersed in dichloromethaneas in the case described above. As a result, the film remained on aglass substrate. From the fact, it is considered that when the thin filmcontaining only dendrimers was irradiated with light, the polymerizationproceeded. This is considered to happen because a photocrosslinkingreaction proceeded among dendrimer molecules by the photoirradiation,and nano-wires were mainly formed.

INDUSTRIAL APPLICABILITY

According to the present invention, a nano-particle and a nano-wire canbe effectively produced.

According to the present invention, a molecular device can be adequatelyproduced by a bottomed-up design.

A nano-particle and a nano-wire according to the present invention canbe used as a liquid crystal material, a functional material, anelectronic functional material, a catalyst, a nano-level electronicelement, a nano-level FET, a toner raw material, additives for plasticssuch as an antistatic agent and a charge donor agent, and a drugdelivery system.

A nano-wire according to the present invention can be used for asuperdense memory material and a light emitting element, which takeadvantage of the periodicity of a level of a plurality of nanometers toa plurality of hundreds of nanometers.

1. A molecular structure having a shell structure obtained by: using amolecular structure constituted by a skeleton portion having a skeletonstructure, and a terminal portion which is arranged in the outer shellof the skeleton portion, has a higher atomic density than that of theskeleton portion and has a plurality of bonding residues, and aphotosensitizer included inside the molecular structure; and joining thebonding residues in the terminal portion by taking advantage of thespectral sensitization of the photosensitizer molecules irradiated withlight.
 2. A molecular device including the molecular structure havingthe shell structure according to claim 1.